Biomarkers of exposure to metals and metalloids have proven to be powerful tools for epidemiologic studies that seek to study associations between exposures and human health effects. The Trace Metal Facility Core Laboratory is an established facility that is jointly supported by the Columbia University P30 NIEHS Center and this SBRP. The laboratory enables numerous investigators to precisely measure a broad range of metals, metabolites, and proteins in biological specimens. The NIEHS Center budget provides support for instrumentation, some (but not all) service contracts, methods development, and pilot study analyses, as well as partial support for the Laboratory Director and the Laboratory Manager. In the current proposal, three biomedical projects (Projects #1, #2 and #3) collectively have proposed that roughly 65,000 biological specimens be analyzed by this Core during the next five years. Thus, the Core requests funding to support the increased personnel and supply costs associated with these services. This laboratory participates in numerous quality control programs and, in that regard, its performance during the past grant cycle has been outstanding. It has anayzed more than 80,000 biological samples during the past five years, supporting many novel research findings derived from four biomedical research projects. The laboratory is equipped with four atomic absorption spectrophotometers, including three graphite furnace instruments. The laboratory also has ICP-MS-DRC instrumentation that allows for the simultaneous measurement of low concentrations of multiple elements in biological samples. The analytical methods to be conducted during the next five years include many that are already in place including: total As and creatinine in urine; Pb, As, and Se in blood; As metabolites in urine and blood. As in toenails, and other methods. One year ago, the Trace Metals Core Laboratory moved into larger and newly renovated space.